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TUV Rheinland Blog

Keep Up-to-Date with Inverter, Converter Regulations

By Fred Z. Zhu, Business Development Manager, Electrical and Product Safety, TUV Rheinland

Are you up-to-date on the regulations governing inverters and converters in the U.S. and Canada?

Here are some new standards, upcoming initiatives and questions yet to be answered.

Fred Zhu

Harmonization of UL 62109-1 with IEC 62109-1 is currently underway to reconcile various standards regulating safety of power converters used in photovoltaic (PV) power systems. That will make it easier for manufacturers to have their products tested for compliance in global markets.

The recent standard IEC 62477-1: 2012 established new safety requirements for power conversion systems and equipment. It covers not only electronic equipment for use in solar power installations but also non-PV products, such as wind power converters (AC – AC).

Make sure to refer to the EN 50438 standard for the grid connection and power quality requirements for micro-generators connected with public low-voltage distribution networks. The requirements may differ by countries.

Relatively new transformer-less inverters are gaining in popularity because of the lower cost and higher efficiency when compared with conventional inverters. They need to comply with the new safety requirements, specified in UL 1741, section 88-100.

In the U.S. and Canada, most inverters are designed for the input working voltage up to 600Vdc. As the input working voltage increases, new requirements need to be considered to handle such an increase to ensure safe operation of the inverters.

The newly developed UL 1699B covers DC arc-fault circuit protection devices intended for use in PV energy systems, as described in Article 690 of the National Electrical Code, NFPA 70. The standard regulates the use of arc detection in high-voltage systems to increase safety, protect people and equipment and prevent catastrophic damage.

In cases where the consumer sells power back to the utility, a built-in meter must accurately measure that amount. The regulations guiding the accuracy of a built-in meter can be found in ANSI C12.1.